1. Field of the Invention
The present invention relates to a circuit breaker, and more particularly, to an abnormal current detection circuit for circuit breaker configured to electrically detect an abnormal current in a circuit, thereby allowing the circuit breaker to break the circuit when the abnormal current flows in the circuit.
2. Description of the Conventional Art
A circuit breaker is a power device for detecting an abnormal current to automatically break the circuit, thereby protecting life, an electrical load device, and a circuit from an accident current in a power supply circuit between the power source and the load, when the abnormal current such as an over current, an electric shortage current, or the like is generated in the circuit. In such circuit breakers, an electric leakage circuit breaker is a circuit breaker having a function of breaking a circuit when detecting an electric leakage as well as the over current and electric shortage current, thereby protecting life, a load device, and a circuit from an accident current. The circuit breaker, as well known in the art, may include a trip mechanism for detecting an abnormal current in a circuit, and a switching mechanism for implementing a trip operation thereby separating a movable contactor from a stationary contactor to break the circuit triggered by the trip mechanism. The trip mechanism may be configured by comprising a trip coil for generating magnetic absorption force when magnetized by a driving current, and an armature to be rotated by the magnetic absorption force of the trip coil. The switching mechanism is configured by comprising a trip spring for providing the driving force of the trip (circuit break), a latch mechanism capable of being moved to a releasing position of the trip spring by the rotational pressure of the trigger mechanism or a locking position of the trip spring in an elastic energy charged state, and a power transmission mechanism for transmitting the elastic energy of the trip spring to the movable contactor to break a circuit.
The abnormal current detection circuit for circuit breaker performs a role of detecting an abnormal current in a circuit and providing an electrical driving signal to the trip coil when the abnormal current is detected.
In the abnormal current detection circuit for circuit breaker, an abnormal current detection circuit for circuit breaker according to the related art is configured with a circuit in which a current signal detected by a current transformer for each phase or zero-phase current transformer in case of an electric leakage circuit breaker is amplified using a half-wave amplifier, and compared with a predetermined reference value using a comparator to determine normality or abnormality, and a driving signal is outputted to the trip coil when abnormality is determined.
However, the abnormal current detection circuit for circuit breaker according to the related art is configured to amplify an input signal from the current transformer using a half-wave amplifier, and therefore, the detection of abnormal current generation may be promptly performed, or delayed by a half wave, i.e., 180 degrees, based on whether the phase of the input signal is started at 0 or 180 degrees. As a result, it may cause a detection delay, for instance, detection delay of maximum 10 ms (millisecond). Such a detection delay in a circuit breaker requiring a high-speed trip has a problem of resulting in the damage of load device, and circuit.
Furthermore, in the abnormal current detection circuit for circuit breaker according to the related art, when configuring the detection circuit thereof with a typical electronic device, the characteristics of the device may vary depending on temperature and production process speed variations, i.e., low-speed production, standard-speed production, and high-speed production, or the characteristics of an integrated circuit may vary in configuring the integrated circuit, thereby causing a problem that the reliable detection of an abnormal current cannot be provided, and the reliable operation of a circuit breaker cannot be guaranteed.